Merge pull request #338 from realm/al-schema-version

Support getting the schema version from unopened realms

CHANGELOG.md

@@ -10,6 +10,7 @@
 * Support relative paths when opening realms
 * Support case insensitive queries
 * Support for indexed bool, string, and int properties
+* Added method to retrieve schemaVersion from an unopened Realm
 
 ### Bugfixes
 * Fix for crash on Android when initializing the Realm module

docs/realm.js

@@ -103,6 +103,17 @@ class Realm {
     write(callback) {}
 }
 
+/**
+ * Get the current schema version of the Realm at the given path.
+ * @param {string} path - The path to the file where the
+ *   Realm database is stored.
+ * @param {ArrayBuffer|ArrayBufferView} [encryptionKey] - Required only when
+ *   accessing encrypted Realms.
+ * @throws {Error} When passing an invalid or non-matching encryption key.
+ * @returns {number} version of the schema, or `-1` if no Realm exists at `path`.
+ */
+Realm.schemaVersion = function(path, encryptionKey) {};
+
 /**
  * The default path where to create and access the Realm file.
  * @type {string}

lib/browser/index.js

@@ -172,6 +172,11 @@ Object.defineProperties(Realm, {
         get: util.getterForProperty('defaultPath'),
         set: util.setterForProperty('defaultPath'),
     },
+    schemaVersion: {
+        value: function(path, encryptionKey) {
+            return rpc.callMethod(undefined, Realm[keys.id], 'schemaVersion', Array.from(arguments));
+        }
+    },
     clearTestState: {
         value: function() {
             util.clearMutationListeners();

src/js_realm.cpp

@@ -149,6 +149,13 @@ static bool SetDefaultPath(JSContextRef ctx, JSObjectRef object, JSStringRef pro
     return true;
 }
 
+inline std::string RJSNormalizePath(std::string path) {
+    if (path.size() && path[0] != '/') {
+        return default_realm_file_directory() + "/" + path;
+    }
+    return path;
+}
+
 JSObjectRef RealmConstructor(JSContextRef ctx, JSObjectRef constructor, size_t argumentCount, const JSValueRef arguments[], JSValueRef* jsException) {
     try {
         Realm::Config config;
@@ -202,9 +209,7 @@ JSObjectRef RealmConstructor(JSContextRef ctx, JSObjectRef constructor, size_t a
             return NULL;
         }
         
-        if (config.path.size() && config.path[0] != '/') {
-            config.path = default_realm_file_directory() + "/" + config.path;
-        }
+        config.path = RJSNormalizePath(config.path);
         
         ensure_directory_exists_for_file(config.path);
         SharedRealm realm = Realm::get_shared_realm(config);
@@ -232,6 +237,39 @@ static const JSStaticValue RealmStaticProperties[] = {
     {NULL, NULL}
 };
 
+JSValueRef RealmSchemaVersion(JSContextRef ctx, JSObjectRef function, JSObjectRef thisObject, size_t argumentCount, const JSValueRef arguments[], JSValueRef* jsException) {
+    try {
+        RJSValidateArgumentRange(argumentCount, 1, 2);
+        
+        Realm::Config config;
+        config.path = RJSNormalizePath(RJSValidatedStringForValue(ctx, arguments[0]));
+        if (argumentCount == 2) {
+            JSValueRef encryptionKeyValue = arguments[1];
+            std::string encryptionKey = RJSAccessor::to_binary(ctx, encryptionKeyValue);
+            config.encryption_key = std::vector<char>(encryptionKey.begin(), encryptionKey.end());
+        }
+
+        auto version = Realm::get_schema_version(config);
+        if (version == ObjectStore::NotVersioned) {
+            return JSValueMakeNumber(ctx, -1);
+        }
+        else {
+            return JSValueMakeNumber(ctx, version);
+        }
+    }
+    catch (std::exception &exp) {
+        if (jsException) {
+            *jsException = RJSMakeError(ctx, exp);
+        }
+    }
+    return NULL;
+}
+
+static const JSStaticFunction RealmConstructorFuncs[] = {
+    {"schemaVersion", RealmSchemaVersion, kJSPropertyAttributeReadOnly | kJSPropertyAttributeDontEnum | kJSPropertyAttributeDontDelete},
+    {NULL, NULL},
+};
+
 JSClassRef RJSRealmConstructorClass() {
     JSClassDefinition realmConstructorDefinition = kJSClassDefinitionEmpty;
     realmConstructorDefinition.attributes = kJSClassAttributeNoAutomaticPrototype;
@@ -239,6 +277,7 @@ JSClassRef RJSRealmConstructorClass() {
     realmConstructorDefinition.callAsConstructor = RealmConstructor;
     realmConstructorDefinition.hasInstance = RealmHasInstance;
     realmConstructorDefinition.staticValues = RealmStaticProperties;
+    realmConstructorDefinition.staticFunctions = RealmConstructorFuncs;
     return JSClassCreate(&realmConstructorDefinition);
 }
 

tests/js/realm-tests.js

@@ -117,6 +117,27 @@ module.exports = BaseTest.extend({
         TestCase.assertEqual(Realm.defaultPath, newPath, "defaultPath should have been updated");
     },
 
+    testRealmSchemaVersion: function() {
+        TestCase.assertEqual(Realm.schemaVersion(Realm.defaultPath), -1);
+        
+        var realm = new Realm({schema: []});
+        TestCase.assertEqual(Realm.schemaVersion(Realm.defaultPath), 0);
+
+        realm = new Realm({schema: [], schemaVersion: 2, path: 'another.realm'});
+        TestCase.assertEqual(Realm.schemaVersion('another.realm'), 2);
+
+        var encryptionKey = new Int8Array(64);
+        realm = new Realm({schema: [], schemaVersion: 3, path: 'encrypted.realm', encryptionKey: encryptionKey});
+        TestCase.assertEqual(Realm.schemaVersion('encrypted.realm', encryptionKey), 3);
+
+        TestCase.assertThrows(function() {
+            Realm.schemaVersion('encrypted.realm', encryptionKey, 'extra');
+        });
+        TestCase.assertThrows(function() {
+            Realm.schemaVersion('encrypted.realm', 'asdf');
+        });
+    },
+
     testRealmCreate: function() {
         var realm = new Realm({schema: [schemas.IntPrimary, schemas.AllTypes, schemas.TestObject]});